1. Field of the Invention
This invention relates to flotation devices and, more particularly, to auxiliary flotation devices which can selectively provide additional ground support for load-bearing vehicles.
2. Description of Prior Art
In prior art proposals, extra flotation devices have been used wherein the tag axle and wheels are raised to such an elevated position that in relation to the center of gravity of the vehicle, there is created an unstable condition during transport while the wheels are in their raised or elevated position. In still other flotation devices, the additional support mechanism for the added wheels is telescoped within the frame of the vehicle during transport. In still other prior art devices, when it is desired to secure extra flotation or ground support for the load-bearing vehicle, the extra flotation wheels are extended to the rear of the vehicle and the tires, mounted on a tag axle, are brought into ground engagement so that the vehicle is additionally supported.
As part of the functional requirements for a satisfactory tag axle, the extra flotation device must be stable and readily positionable in ground engagement and then raised to a second position known as the "transport" position. While positioned in transport mode, the extra flotation wheels should interfere as little as possible with the other functions of the vehicle. While these objectives appear at first blush to be simple and easily attainable, they are by no means obvious and have, indeed, occupied the art for a considerable period of time without an entirely satisfactory solution.